Speaker unit



y 1953 J. MCDONALD 2,835,334

SPEAKER UNIT Filed May 6, 1954 ,4 y. rs,

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' IN VEN TOR. 2 (jazz/as fll-Zoxza/i United States Patent SPEAKER UNIT James McDonald, Martinez, Calif.

Application May 6, 1954, Serial No. 427,960

1 Claim. (Cl. 181-31) This invention relates to speaker units and is particularly concerned with units for use with standard radios, television sets and like devices for enhancing the resonance, tone values and amplitude of sound produced by such instrumentalities.

While the volume, quality and fidelity of sound reproduction, by electrical transmission, as in radios and television sets, is normally of good quality, it frequently occurs particularly with sets of limited dimension that resonance and tone values are restricted by the small size of the speaker units which may be accommodated in such devices. The present invention is directed towards means for improving the characteristics of sound, produced by speakers in general, and although particularly efficient and effective in combination with speakers of limited size, the invention is broadly applicable to use in improving the sound reproduction of a wide variety of sizes, types and characters of speakers generally.

it is, therefore, among the general objects of the invention to provide means operable as an accessory to loud speakers for enhancing the quality of the sounds produced thereby.

More specifically, it is an object of the present invention, to provide for use with a speaker, a resonance chamber to receive the sound waves and act therewith to improve the quality thereof.

Another object of the invention is to provide within a sound receiving chamber, means responsive to sound waves for influencing their characteristics to the end that better tone and resonant qualities are imparted thereto.

A further object is to provide an accessory for radios, television sets and the like, operable to form a combined stand and sound modifier therefore.

Other objects and features of the present invention will be apparent from a consideration of the following specification, taken in conjunction with the accompanying drawings, in which:

Figure 1 is a side elevation of one preferred form of the present invention, shown in radio supporting and cooperating position;

Figure 2 is a perspective view of that form of the device, shown in Figure l, with the radio removed;

. Figure 3 is a vertical sectional view of the device as taken on a plane indicated by the line 3-3 of Figure 2, and

Figure 4 is an illustration of a modification of the device for use by direct attachment to an electrical speaker unit.

Referring now more particularly to the drawings, the numeral refers generally to the hollow .L-shaped housing of the present device. It will be understood that while the housing may be variously constructed as to mechanical connection of the elements thereof, and as to the materials employed, it may for present purposes be considered as comprising side and end walls of relatively light, thin and durable board material, such as wood, plastic, plywood or composition board, and individual pieces thereof may be joined by glue or united as integral parts.

As hereinbefore indicated, the body is hollow and generally L-shaped in vertical cross section, including an upstanding resonance chamber portion 11, and a communicating horizontal sound wave delivery chamber 12. While the proportions and dimensions of the device are not critical, and their design may be dictated by acoustical requirements, it is preferable that as here shown the resonance chamber 11 extend the full height and width of the radio or other instrument with which it is to be associated, or at least to register with the location of the speaker thereof. Similarly it is preferable that the delivery chamber 12 be equal to the dimensions of the base of the instrument so as to provide an adequate support, therefore, harmonizing in appearance therewith.

The top of the chamber 11 is closed by a cover 13 and the rear wall 14 is similarly closed by an imperforate panel extending to the bottom of the chamber 12. The end walls 15 of both chambers are also closed by solid end pieces 16. The front wall 17 of the chamber 11, however, is perforated being provided with apertures 18 of such size, number and configuration as to readily receive sound waves produced by the speaker of the radio indicated by the numeral 20. Thus, it will be seen that the chamber 11 constitutes a sound receiving resonance chamber sealed but for the sound receiving openings 18, but in open sound transmitting communication with the chamber 12.

As referred to, the chamber 12 is disposed horizontally beneath the radio 20, its upper imperforate surface 21 forming a support therefore. While the invention contemplates the design of radio and unit as a single structure, the present illustration contemplates support of a separate table-type radio on the surface 21. in any event it may be noted that a space is desirable between radio and chamber surface so as to provide ventilation and to preclude undesirable vibration of the chamber surface.

The rear of the chamber 12 is in open communication with chamber 11, and its sides 22 and bottom 23 are of the same type of imperforate wall construction as setforth with respect to the top end and rear wall of chamber 11. The front end of chamber 12, however, is open for the emission of the sound waves from chamber 11, an ornamental sound transmitting grill or screen 2d being provided for the sake of appearance. Chamber 12, therefore, provides for the directionalguidance of sound waves from the chamber 11 to delivery forwardly of the set 20 in a manner to appropriately mingle with sound waves directly emitted therefrom.

An important feature of the invention is the provision within the resonance chamber 11 of a sound board or bathe 25, freely suspended by wires 26 from a hanger rod 27, located midway between the front and rear walls of the chamber. The member 25 is of course of less length than that of the chamber 11 and also of less height so as to be supported for free pivotal swinging movement on the rod 27. The structure, composition and acoustic character of the member 25 may vary as dictated by specific qualities which are to be accentuated; however, for the present purposes the member may be of the same material and thickness of the walls of the chambers 11 and 12. The area of the member 25 is preferably slightly larger than the size of the speaker with which it is to be used.

In use, as the sounds emitted from the unit 20 enter the chamber 11 through the ports 18, the chamber itself resonates therewith to enhance their tonal qualities and therewith the member 25 may swing and vibrate acting as a sounding board and/ or a bafiie. In use it has been found that this means of handling sound waves provides an improved resonance and tonal quality. The sound waves thus resonated, modulated and/or amplified pass forwardly through the chamber 12 and are emitted through the grill or screen 24 to greatly enhance the direct sound propagated by the instrument 20.

lnaddition to the effectiveness of the sounding board in the resonance chamber as a responsively vibrating element, it will be noted that by virtue of its free swinging suspension it may respond bodily to the impingement of sound Waves to vary the space between it and the front of the chamber permitting an enhanced area for wave expansion in response to increased wave strength. It wil further be noted that since the lower end of the panel enters the rear throat of the chamber 12, a directional effect is administered to assist in the forward propagation of the Waves with minimum distortion.

in that form of the invention illustrated in Figure 4, the front wall 3% of the vertical resonance chamber is shown as imperforate, while the rear wall 31 has mounted therethrough a loud speaker 32. in this construction, the sound Waves from the speaker 32 are modified, amplified, resonated and/or bathed in the same manner as referred to with respect to that form of the invention shown in Figures 1 to 3 inclusive.

in considering the invention as herein set forth it will, of course, be understood that the embodiment presented is but one of the many forms of which the present inven tive concept may partake and that in the practice of the invention numerous changes, modifications and the full 4 use of equivalents may be resorted to without departure from the spirit or scope of the invention as set forth in the appended claim.

What I claim is:

A sound modifier, particularly for table model radios and the like having small speakers, said modifier comprising an L-shaped housing defining a vertical and a horizontal chamber in open communication at their juncture, said horizontal chamber being of a size generally corresponding to that of the radio with which it is to be used and forming a support for such radio, said vertical chamber being of a height generally corresponding to that of such radio and having ports in the front wall thereof for confronting the back of the radio for the admission of sound waves into said housing, and a panel swingably suspended in said vertical chamber for intercepting and modifying the sound waves.

References Cited in the file of this patent 

